1. Field of the Invention
The present invention relates to the detection of a smoke situation or a fire situation in a vehicle, for example in an aircraft. In particular, the present invention relates to a smoke alarm system for an aircraft, as well as to a method for detecting the smoke situation in a space of an aircraft.
2. Technological Background
Presently available smoke warning systems for mobile applications and correspondingly limited installation options (aircraft, railway, submarine etc.) operate with optical smoke warning transmitters. These smoke warning transmitters use the diffused-light principle with a specified alarm threshold. In the case where there is no smoke or there are no particles, the receiver does not receive a signal because there is a barrier between the light source and said receiver. However, if smoke particles (or other particles) are encountered in this region, then the light is diffused and the receiver registers a corresponding signal rise. If this signal rise exceeds a specified threshold value, the smoke warning system issues an alarm, for example an intermittent light signal at some other location, or an alarm sound.
However, in a disadvantageous way, all types of aerosols, i.e. not only smoke particles, cause light diffusion and can thus erroneously cause smoke warning transmitters to assume an alarm state. In practical application it has been shown that in such smoke warning transmitters, for example fog, dust or even the use of insecticides can cause false alarms. In most applications such false alarms pose a safety risk; in this context evacuation of aircraft or ships is pertinent.
For this reason it is advantageous to reduce, and there is a need for reducing, the probability of false alarms, which probability at times is more acute in the case of mobile applications due to quickly changing ambient conditions.